<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<style>
    div{
        width:200px;
        height:200px;
        background-color: red;
    }

    .charge{
        width:300px;
        height:300px;
        background-color: pink;
    }
</style>
<body>
    <div class="one">文本内容</div>
    <script>
        var test = document.querySelector('div');
        test.onclick = function(){
            this.className = 'charge';
        }
    </script>
</body>
</html>